Wie genau asynctask verwenden?

Question

Ich habe Tage damit verbracht, einen Datei-Explorer zu implementieren. Ich stecke nur an einem Teil fest. Bilder werden zu langsam geladen! Also bin ich zu asynctask umgezogen. Ich kann den Bildbetrachtungsinhaber nicht korrekt aktualisieren. Hier ist mein Code:

@Override 
public View getView(final int position, View convertView, ViewGroup parent) { 




    File file=new File(String.valueOf(filenames[position])); 
    if(file.isDirectory()){ 
     img=R.drawable.folder; 
    } 

    else{ 
     img=getImage(filenames[position]); 
    } 


    ViewHolder viewHolder = null; 
    if (convertView == null) { 
     LayoutInflater inflator = LayoutInflater.from(getContext()); 
     convertView = inflator.inflate(R.layout.list_item, null); 
     viewHolder = new ViewHolder(); 
     viewHolder.tv = (TextView) convertView.findViewById(R.id.textView1); 
     viewHolder.cb = (CheckBox) convertView.findViewById(R.id.checkBox1); 
     viewHolder.iv= (ImageView)convertView.findViewById(R.id.imageView); 
     viewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { 

      @Override 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
       int getPosition = (Integer) buttonView.getTag(); // Here we get the position that we have set for the checkbox using setTag. 
       myList.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state. 
      } 
     }); 
     convertView.setTag(viewHolder); 
     convertView.setTag(R.id.textView1, viewHolder.tv); 
     convertView.setTag(R.id.checkBox1, viewHolder.cb); 
     convertView.setTag(R.id.checkBox1, viewHolder.iv); 
    } 
    else { 
     viewHolder = (ViewHolder) convertView.getTag(); 
    } 

    viewHolder.iv.getLayoutParams().height = 80; 
    viewHolder.iv.getLayoutParams().width = 80; 
    viewHolder.cb.setTag(position); 
    final ViewHolder ViewHolder= viewHolder; 

    ViewHolder.tv.setText(myList.get(position).getName()); 
    ViewHolder.cb.setChecked(myList.get(position).isSelected()); 

    Log.v("this","viewHolderMT: "+String.valueOf(viewHolder)+"position: "+position); 

    final View finalConvertView = convertView; 

    class myTask extends AsyncTask<Integer,Bitmap,Bitmap>{ 

     int pos; 
     public myTask(int pos){ 
      this.pos=pos; 
     } 

     @Override 
     protected Bitmap doInBackground(Integer... params) { 
      Bitmap thumb=null; 
      //Log.v("this","position: "+String.valueOf(position)); 

      if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){ 
       thumb = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(String.valueOf(filenames[pos])), 64, 64); 
       publishProgress(thumb); 
       Log.v("this","In DIB: "+String.valueOf(thumb)); 
       //Log.v("this","filenameDOI: "+String.valueOf(filenames[pos])+" positionDOI: "+String.valueOf(pos)); 
      } 
      else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")){ 
       thumb=ThumbnailUtils.createVideoThumbnail(filenames[pos].getPath(), MediaStore.Video.Thumbnails.MINI_KIND); 
       Log.v("this","In DIB: "+String.valueOf(thumb)); 
       publishProgress(thumb); 

      } 
      return thumb; 
     } 
     @Override 
     protected void onProgressUpdate(Bitmap... thumb){ 
      if(isCancelled()){ 
       return; 
      } 

      ViewHolder v= (ViewHolder)finalConvertView.getTag(); 

      Log.v("this","viewHolderPU: "+String.valueOf(v)+"position: "+pos); 
      if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){ 
       //Log.v("this","filenameOPE: "+String.valueOf(filenames[pos])+" positionOPE: "+String.valueOf(pos)); 
       v.iv.setImageBitmap(thumb[0]); 
       Log.v("this","In PU: "+String.valueOf(thumb[0])); 
      } 
      else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")){ 

       v.iv.setImageBitmap(thumb[0]); 
      } 
     } 
     @Override 
     protected void onPostExecute(Bitmap thumb){ 



     } 
    } 

    myTask m=new myTask(position); 
    m.execute(); 

    return convertView; 



} 

Bilder auf verschiedene imageviews laden, auch die imageviews halten auf mit neuen Bildern auf beiden Scrollen und sonst zu blinken. Ich bin so nah an der Lösung, aber irgendwie immer noch fest.

Answer 1

Sie erhalten Ergebnis von AsyncTask in onPostExecute(). Die onProgressUpdate() ist für Dinge wie Fortschrittsbalken auf der Benutzeroberfläche und solche Dinge angezeigt.

Versuchen Sie, Ihren Code von onProgressUpdate() zu onPostExecute() zu verschieben.